The present invention relates to a receptacle box for use in a pavement or similar structure. More specifically, the present invention relates to a void-forming box, or preform, that can be embedded in a poured concrete pavement or similar structure to accept and support a light fixture.
Pavements are made from a variety of materials, including asphalt, concrete, brick, and gravel, for a variety of purposes, such as roadways, runways, driveways, sidewalks, patios, and so forth. In many situations, it is desirable to provide illumination on the surface of the pavement, to illuminate a centerline or an edge of the pavement, for example. Pavements are illuminated with both reflective and active devices. Reflective devices, such as reflective paint or reflectors, reflect light from an light source, such as a car's headlamps. Reflective devices are relatively inexpensive, easy to apply, and robust. However, reflective devices must be illuminated by an external light source and often provide reflective illumination over only a narrow viewing angle.
Active devices have a light source, such as a lamp or fiber optic cable, that emits light. While active devices do not rely on an external light source, active devices require some sort of power to be delivered to, or contained within, the device. The power lines that deliver power to active devices usually run beneath the surface of the pavement. This protects the power lines against damage from the traffic on the surface of the pavement and provides a smooth pavement surface.
One active system for use with asphalt pavements, such as airport runways, runs power lines through a slot cut in the pavement to a lamp that is placed in a divot that is chipped out of the pavement. The slot is then filled with a sealing material. Such a system is limited in utility as the lamps are typically small so that they may sit within the divots and be protected from the weight of the tires. These types of systems are not generally used in concrete or brick pavements because of the difficulty of forming the slots and divots.
Another system uses fiber optic cable to distribute light from a lamp near the pavement to bricks or paving blocks that have a hole drilled through the brick and a small lens on the surface of the brick. The fiber optic cable is brought to the backside of the brick and optically coupled to the lens to provide a small dot of light on the surface of the brick. Unfortunately, this system is impractical for use with formed-in-place pavements, such as poured concrete pavements, because any repair or replacement of a part often requires the use of a jackhammer or sledgehammer to destroy the pavement in order to gain access to the part, and then the pavement must be repaired.
Conventional electrical receptacles, junction boxes, pull boxes, and similar devices exist for forming voids in poured concrete structures, such as floors of buildings, but are unsuitable for accepting and supporting light fixtures for several reasons. A common problem with such devices is the labor and total process time required to set the devices to grade. Typically, such devices are set to grade using a wet-set technique or a trimming technique. The wet-set technique involves pouring a patty of concrete at the intended location of the receptacle and pressing the receptacle into the concrete until the receptacle is at the proper grade. This is a time consuming and labor-intensive process that requires mixing and pouring of concrete before the slab may be poured, and does not allow fine adjustment of the height of the receptacle. Preforms used in trimming techniques typically extend above the height of the intended slab. The preform is set to an approximate height, and the excess is trimmed off after the slab is poured. This technique is also time consuming, and does not provide accurate control of the depth of the void.
Controlling the depth of the void is important when a preform is intended to accept a subsequent component of a particular height, such as a light fixture, because the component may stick out of, or be sunk below, the pavement if the height of the preform is not accurately controlled. Furthermore, conventional receptacles and preforms typically have no means to support a light fixture, have structures that would interfere with insertion of a component, such as screw tabs or seating rims, and do not provide any storage space for coiling wire to allow the light fixture to be removed and serviced.
Therefore, a device or system allowing illuminating devices to be installed in formed-in-place pavements is desirable. It is further desirable that any such device or system provide support for the traffic passing over the pavement, and allow access to the device for maintenance or replacement.